Letters to the Prime Minister: The Future of Educationedited by Ted Wragg114pp, New Vision Group, £8

Its title may be more suited to a cheesy 1970s pop band than a collection of eminent academics, but the New Vision group brings together some of the country's most important educationalists at a key political moment. The epithet "new" does not do them full justice either; according to the waspish, witty Ted Wragg, New Vision represents a group of people — "loose, in the nicest sense of the word" — who have been meeting informally for well over a decade.

A sense of history has some definite advantages, however, especially in relation to education: as long ago as 1993, the group warned of the dangers of seeing "children as commodities, parents as consumers, schools as competitive businesses, teachers as technicians, the curriculum as a set of bureaucratic requirements, accountability as narrowly conceived test scores ... " All of which sounds eerily familiar in 2005.

Luckily, progressive educationalists are a remarkably patient and tenacious lot. They have had to be. And with this volume of extended political postcards, each one topped and tailed in the hand of the individual author — a nice personalising flourish, this — they take the opportunity to address our newly elected government. So we have bulletins on the state of play (and need for change) in areas as diverse as black under-achievement in school, the agenda for special needs, the fast-shrinking role of local authorities, the importance of a Learners' Charter for 14- to 19-year-olds and the continuing inequities of the state/private divide.

There is a broad consensus on New Labour's legacy from 1997 to 2005. Funding has been generous, and schemes like Sure Start and Excellence in Cities have been welcomed in hard-pressed areas. Education itself takes an ever higher profile in national life. On the other hand, we have witnessed the serious, some say terminal, demoralisation of the teaching profession, excessive testing and target-setting within the framework of an often stifling curriculum and, in the dubious name of choice and diversity, the introduction of a competitive market between schools. This last reform has accelerated the fragmentation of public educational provision; according to Britain's premier educational administrator, Tim Brighouse, there is now a "dizzyingly steep pecking order" of schools, particularly in the big cities.

Geoff Whitty welcomes specialist schools as a means of updating the comprehensive vision while others suspect them of engineering a return to selection. But on so many of New Labour's initiatives, or lack of them, there is broad agreement. Academies, with their large dollops of private money and private control, the continued existence of 160-plus grammar schools and, of course, the charitable privileges of the private sector are all seen as blocks to a fairer education system.

Admissions policy emerges as a central theme. Despite all its claims to be improving parental choice, the policy of the last government meant more and more schools chose their pupils, rather than pupils choosing them; just under half of faith and foundation schools operate admissions policies that work to their own advantage. According to Anne West, many give "priority to pupils who are likely to benefit the school in terms of its league table position, and who are easier to teach", thus overloading other schools with the educationally and socially disadvantaged.

"Does this matter?" West asks quietly. "In terms of social justice it does." Here's one of the big problems, then. So far, New Labour has talked the talk on social justice, inclusion and the rest, but in so many bureaucratic, technical ways its policies have served to confirm established structures. The new freedoms given to faith and foundation schools, and some academies, seem set to reintroduce the old, poisonous grammar and secondary modern divide, a division that will be sweetened and obscured by ghastly modern edu-jargon with all its jolly earnest claims to promote everything from diversity to personal faith, excellence to stretching.

Most contributors to this volume are too polite, or politic, to spell it out, but it is painfully clear to most educationalists that Blairism, and in particular the No 10 policy unit, has long been hostile to the comprehensive legacy, yet unable decisively to reject it. Up till now, that is. Pre-election, there were hints from Number 10 that, should he win a third term, Blair would finally break with the comprehensive principle and openly return to some version of selection by ability, a political development that would bring untold disasters in its wake.

The authors of Letters to the Prime Minister live in hope and the real world; this slim volume represents something between a friendly pinch of the cheek and a firm hand of warning. It would take a more pessimistic or tired or thoroughly fed-up observer to conclude that no government will ever make the necessary reforms to education until it has a leadership with a deeper understanding of the link between education and social disadvantage and a genuine faith in the profound, as yet unseen, possibilities of the comprehensive ideal.

• Melissa Benn's books include Madonna and Child: Politics of Modern Motherhood (Vintage)